Preheat oven to 425, and line a sheet pan with parchment paper.

Mix salt, pepper, garlic, and dill in a small bowl and set aside.

Using paper towels or a clean cloth, blot fish filets until dry. Season both sides with spice mixture.

Layer the leek pieces and lemons in 4-6 columns across the lined sheet pan, making a bed for each filet to sit on. Place filets over the lemon and leeks. Top each fillet with remaining leek and lemon slices, and sprinkle with fennel fronds.

Bake in preheated oven for 20-25 minutes or until fish is no longer opaque and cooked through. If your filets are small and/or thin, begin checking them after 15 minutes.

Remove from oven and serve immediately with extra lemon on the side. Be sure and remind your diners to squeeze the baked and/or fresh lemon over the filets.